Small Form-factor Pluggable (SFP) units are standardized units adapted to be inserted within a chassis. The MSA standard describes the size of the SFP unit, so as to ensure that all SFP fully-compliant and partially-compliant units may be inserted smoothly within one same chassis, i.e. inside cages, ganged cages, stacked cages and belly-to-belly cages.
SFP units may be designed with various types of exterior connectors, such as coaxial connectors, optical connectors, and any other type of electrical connector.
As SFP units are small in dimensions, it is possible to limit the size of the chassis required to host several units simultaneously. And with the constant reduction of the electric, electronic and optic components used within the SFP units, the only limitation known today is due to the size of the connectors from which signals are received and transmitted there from.
However, removal of a SFP unit from a chassis is a problem due to the small size and relative fragility of actuators. SFP units are typically kept in place by use of a latch on a bottom face. Removing a SFP unit requires applying sufficient pulling or pushing force to move a cage latch or a latch itself, to overcome a resistance of a spring loaded latch.
The SFP unit may thus be broken by an excessive or misapplied force to disengage the SFP unit from the chassis.